Final answer:
Kerosene is used in the PUREX process as a diluent for tributyl phosphate to create an organic phase that remains separate from the aqueous phase, facilitating the extraction of uranium and plutonium while minimizing the solubility of unwanted fission products.
Step-by-step explanation:
The PUREX (Plutonium Uranium Redox EXtraction) process is a chemical method used to reprocess spent nuclear fuel to extract valuable fissile materials, such as uranium and plutonium, for reuse. In this process, kerosene is used as a diluent for tributyl phosphate (TBP), which acts as the extracting agent.
TBP is mixed with kerosene to obtain a suitable concentration for the extraction process. Kerosene is chosen because it is a non-polar solvent that does not mix with water, ensuring that the organic phase (containing TBP and kerosene) and the aqueous phase (containing the nuclear fuel residue) remain separate.
This separation is crucial for the selective extraction of uranium and plutonium from the fission products present in the spent nuclear fuel.
The non-polar nature of kerosene also helps to minimize the solubility of unwanted fission products into the organic phase, improving the efficiency of the extraction process.